Separation Of Products Research Articles

Heterologous expression of bacterial tyrosinase and its applications in biological hair dyeing and DOPA modification of hydrolyzed silk fibroin

Tyrosinase is a copper-containing polyphenol oxidase widely applied in the food, cosmetics, pharmaceutical, and other industries. Currently, the production of commercial tyrosinase primarily relies on extraction from fungi, which has high costs, low purity, low specific activity, and poor stability. The objective of this study is to obtain highly expressed bacterial tyrosinase with potential for industrial applications. The bacterial tyrosinases from five different sources were heterologously expressed in Escherichia coli BL21(DE3), and the tyrosinases TyrBm and TyrVs derived from Bacillus megaterium and Verrucomicrobium spinosum were obtained with the enzyme activities of (16.1±0.2) U/mL and (48.6±0.9) U/mL, respectively. After protein purification, we compared the enzymatic properties of TyrBm and TyrVs, which revealed that TyrVs exhibited better thermal stability and higher substrate specificity than TyrBm. On the basis of characterizing TyrVs with high catalytic performance, we established a biological hair dyeing system based on TyrVs catalysis to achieve in-situ catalytic hair dyeing. The color washing fastness test measured the ∆E value less than 7.38±0.64 after simulated 14-day cleaning. To facilitate the rapid separation of catalytic products and enzymes, we successfully constructed an immobilized enzyme TyrVs-CipA dependent on self-assembly label CipA and applied this enzyme in the DOPA modification of hydrolyzed silk fibroin (HSF). The immobilized enzyme continuously catalyzed HSF for more than seven cycles, resulting in a single DOPA modification degree exceeding 70.00%. Further investigations demonstrated that DOPA modification enhances the scavenging activity of HSF towards DPPH and O2- radicals by 507.80% and 78.23%, respectively. This study provides a technical foundation for the development of environmentally friendly biological hair dye based on tyrosinase and biomaterials for tissue engineering.

Theoretical Study on the Mechanism of Ru(II)-Catalyzed Intermolecular [3 + 2] Annulation between o-Toluic Acid and 3,5-Bis(trifluoromethyl)benzaldehyde: Octahedral vs Trigonal Bipyramidal.

Density functional theory was utilized to investigate the mechanism of Ru(II)-catalyzed aromatic C-H activation and addition of aromatic aldehydes. The proposed catalytic cycle consists of C-H bond activation, aldehyde carbonyl insertion for C-C coupling, lactonization for the formation of the final product, product separation, and catalyst recovery. Our calculations suggest that Ru(OAc)2(PCy3) (referred to as CAT) is the most favorable active catalyst, facilitating the C-H bond activation to form a five-membered ring cycloruthenium intermediate (INT2). Subsequently, the aromatic aldehyde reactant 2a enters the Ru coordination sphere, accelerating the C-C coupling and lactonization for the formation of the final product. The involvement of acetate assists in the final product separation, while INT1 re-enters the Ru coordination sphere to initiate a new catalytic cycle. Utilizing the energetic span model, the apparent activation free energy barrier was computed to be 34.3 kcal mol-1 at 443 K. Furthermore, exploration of the reaction mechanism in the absence of phosphine ligands identified Ru(OAc)2(p-cymene) as the most favorable active catalyst. The derived apparent activation free energy barrier offers a comprehensive explanation for the experimentally observed yields. Additionally, we have examined the disparities between the octahedral and trigonal bipyramidal structures of the catalysts concerning their effects on the reaction mechanisms and apparent activation free energy barriers.

Design and Optimization of Key Parameters for a Machine Vision-Based Walnut Shell–Kernel Separation Device

The separation of walnut kernels and shells has long been regarded as a bottleneck, limiting processing efficiency, product quality, and industry advancement. In response to the challenges of improving separation accuracy and the inadequacy of existing equipment for meeting industry demands, this paper proposes an innovative walnut shell–kernel separation device based on machine vision technology. An experimental system was constructed, and key parameters were optimized to enhance its performance. The device comprises five main modules: material conveyance, image acquisition, control module, sorting module, and frame. Differential separation technology is used to convert the walnut material group into a stable particle flow, addressing the issue of missed selections due to material blockages. An enhanced YOLOv8n algorithm improves small object detection and interference resistance, enabling accurate identification of walnut kernels. The Box–Behnken Design and Artificial Neural Network prediction model was used to determine the optimal operating parameters for the device. Experimental results showed that effective differential separation was achieved when the dual-stage conveyor system operated at speeds of 0.2 m/s and 1 m/s. The improved I-YOLOv8n algorithm reached an accuracy of 98.8%. Using the neural network model, the optimal operational parameters were determined: an air pressure of 0.72 MPa, a jetting component angle of 10.16°, and a sorting height of 105.12 cm. Under these conditions, the device achieved an actual cleaning rate of 93.56%, demonstrating outstanding separation performance. Compared to traditional separation methods, this device offers significant advantages in terms of efficiency, quality, and ease of operation, providing new technological pathways and support for the automation and intelligent transformation of the walnut processing industry. In the future, the device is expected to undergo further improvements to meet broader market demand and serve as a reference for the separation of other agricultural products.

Unraveling Molecular Diffusion Behaviors on the Acidic Sites of H‐ZSM‐5 Zeolite Using Time‐Resolved In Situ FT‐IR Technique

AbstractZeolites, renowned for their abundant crystalline structures and moderate acidities, have garnered significant attention in industrial chemical processes. Among them, the diffusion behaviors of various hydrocarbons within zeolite play a pivotal role due to their profound impact on product selectivity and separation efficiency. While acid sites are essential in determining the catalytic performance of zeolites, their effect on intra‐crystalline diffusivities has often been neglected in catalyst design. Herein, we employ a homemade time‐resolved in situ Fourier Transform Infrared (TR in situ FT‐IR) spectroscopy to investigate the intricate interplay between Brønsted acid sites and various probe molecules. Our study reveals that an augmentation in the density of Brønsted acid sites within H‐ZSM‐5 zeolites remarkably enhances the diffusivity of 1‐butene, in stark contrast to the behavior observed for iso‐butane. This contrasting effect in diffusivity is attributed to the distinct nature of interactions between alkenes and alkanes with Brønsted acid sites. Specifically, the π‐H interactions between alkenes and acid sites act as a driving force, propelling the alkene molecules forward through the zeolite pores. These findings offer valuable insights into designing tailored zeolites with specific acid site properties, controlling the transport behaviors of various probe molecules, and promising new avenues for catalysis and separation.

Membrane‐Free Electrocatalytic Co‐Conversions of PBS Waste Plastics and Maleic Acid into High‐Purity Succinic Acid Solid

AbstractPlastic pollution, an increasingly serious global problem, can be addressed through the full lifecycle management of plastics, including plastics recycling as one of the most promising approaches. System design, catalyst development, and product separation are the keys in improving the economics of electrocatalytic plastics recycling. Here, a membrane‐free co‐production system was devised to produce succinic acid (SA) at both anode and cathode respectively by the co‐electrolysis of polybutylene succinate (PBS) waste plastics and biomass‐derived maleic acid (MA) for the first time. To this end, Cr3+‐Ni(OH)2 electrocatalyst featuring much enhanced 1,4‐butanediol (BDO) oxidation reaction (BOR) activity has been synthesized and the role of doped Cr has been revealed as an “electron puller” to accelerate the rate‐determining step (RDS) in the Ni2+/Ni3+ cycling. Impressively, an extra‐high SA production rate of 3.02 g h−1 and ultra‐high apparent Faraday efficiency towards SA (FEapparent=181.5 %) have been obtained. A carbon dioxide‐assisted sequential precipitation approach has been developed to produce high‐purity SA and byproduct NaHCO3 solids. Preliminary techno‐economic analysis demonstrates that the reported system is economically profitable and promising for future industrial applications.

Membrane-Free Electrocatalytic Co-Conversions of PBS Waste Plastics and Maleic Acid into High-PuritySuccinic Acid Solid.

Plastic pollution, an increasingly serious global problem, can be addressed through the full lifecycle management of plastics, including plastics recycling as one of the most promising approaches. System design, catalyst development, and product separation are the keys in improving the economics of electrocatalytic plastics recycling. Here, a membrane-free co-production system was devised to produce succinic acid (SA) at both anode and cathode respectively by the co-electrolysis of polybutylene succinate (PBS) waste plastics and biomass-derived maleic acid (MA) for the first time. To this end, Cr3+-Ni(OH)2 electrocatalyst featuring much enhanced 1,4-butanediol (BDO) oxidation reaction (BOR) activity has been synthesized and the role of doped Cr has been revealed as an "electron puller" to accelerate the rate-determining step (RDS) in the Ni2+/Ni3+ cycling. Impressively, an extra-high SA production rate of 3.02 g h-1 and ultra-high apparent Faraday efficiency towards SA (FEapparent=181.5%) have been obtained. A carbon dioxide-assisted sequential precipitation approach has been developed to produce high-purity SA and byproduct NaHCO3 solids. Preliminary techno-economic analysis demonstrates that the reported system is economically profitable and promising for future industrial applications.

Suppressing Protodeboronation in Cu-Mediated 19F/18F-Fluorination of Arylboronic Acids: A Mechanistically Guided Approach Towards Optimized PET Probe Development.

Fluorinated arenes play a crucial role in drug discovery, specialty materials, and medical imaging. Although several variants for Cu-mediated nucleophilic fluorination of arylboronic acids and derivatives have been developed, these protocols rarely address the occurrence and control of protodeboronation, which greatly complicates product separation and can compromise the effectiveness of a radiotracer for in vivo imaging. Consequently, simpler and more efficient procedures are needed to allow rapid 18F/19F-fluorination of both arylboronic acids and esters while minimizing protodeboronation. Mechanistic controls revealed that in addition to a high temperature, strong donor ligands such as acetonitrile and pyridine accentuate a Cu-mediated protodeboronation. This observation guided the optimization of a ligandless procedure, with t-BuOH as solvent, to activate fluoride under milder conditions at lower temperatures minimizing protodeboronation. Additionally, a new copper salt, Cu(ONf)2 was employed to further improve the fluorination efficiency. A large range of functional groups are tolerated under the new procedure, which is complete within 30 minutes at a temperature of 60 °C, and affords fluorinated arenes and heteroarenes in 39 % to 84 % yield. With minimal modifications, the protocol can also be applied in 18F-radiofluorination, affording radiochemical conversions (RCCs) between 17 and 54 % with minimal protodeboronation compared to previously established protocols.

Toward Methanol Production by CO2 Hydrogenation beyond Formic Acid Formation.

ConspectusThe Paradigm shift in considering CO2 as an alternative carbon feedstock as opposed to a waste product has recently prompted intense research activities. The implementation of CO2 utilization may be achieved by designing highly efficient catalysts, exploring processes that minimize energy consumption and simplifying product purification and separation. Among possible target products derived from CO2, methanol is highly valuable because it can be used in various chemical feedstocks and as a fuel. Although it is currently produced on a plant scale by heterogeneous catalysis using a Cu/ZnO-based catalyst, a limited theoretical conversion ratio at high reaction temperatures remains an issue. In addition, a catalytic system that can be adjusted to accommodate a variable renewable energy source for the synthesis of methanol is more desirable than current continuous-operation systems, which require a reliable energy supply. Recently, significant progress has been made in the field of homogeneous catalysis, which primarily relies on an indirect route to synthesize methanol via the hydrogenation of carbonate or formate derivatives in the presence of additives and solvents. However, homogeneous catalysis is inappropriate for industrial-scale methanol production because of the inefficient separation and purification processes involved.In this Account, we demonstrate a novel approach for methanol production under mild reaction conditions by CO2 hydrogenation catalyzed by multinuclear iridium complexes under heterogeneous gas-solid phase conditions without any additives and solvents. One of the aims of this Account provides insights for overcoming the barriers for efficient CO2 hydrogenation by focusing on catalyst design, specifically by incorporating varying functionalities into the ligand. The fundamental strategy entails activating hydrogen molecule and enhancing the hydricity of the resulting metal-hydride species, which is based on the following two concepts of catalyst design: (i) Activating a metal-hydride by electronic effects; and (ii) accelerating H2 heterolysis. We have elucidated the mechanism for accelerating H2 heterolysis using a state-of-the-art catalyst that contains an actor-ligand that responds to or participates in catalysis as opposed to a classical spectator-ligand.We have also demonstrated a novel heterogeneous catalysis using a molecular catalyst as a key step for the hydrogenation of CO2 to methanol beyond formic acid formation. The dehydrogenation of formic acid as a reverse reaction of formic acid hydrogenation is strongly favored in acidic aqueous solution. To circumvent the equilibrium limitation, we have envisioned an alternative route that both prevents the liberation of formic acid into the reaction medium, and develops a multinuclear complex to facilitate the transfer of multiple reactive hydrides. The unconventional gas-solid phase catalysis is capable of preventing the liberation of formate species and promoting further hydrogenation of formic acid through multihydride transfer.This novel catalytic system, which is the fusion of a molecular catalyst in heterogeneous catalysis, provides high performance for methanol synthesis through a sophisticated catalyst design and straightforward separation processes. A detailed mechanistic analysis of molecular catalysts in the gas phase would lead to significant progress in the field of Surface Organometallic Chemistry (SOMC).

Supramolecular assembly strategy of modified starch chains for achieving recyclable emulsion biocatalysis within a narrow pH range

Stimuli-responsive Pickering emulsions are promising in biocatalysis for their ease of product separation and emulsifier recovery. However, pH responsiveness, though simple and cost-effective, faces challenges in precise control and narrow transition ranges, limiting its use in enzymatic catalysis. Herein we introduced amorphous octenyl succinic anhydride-modified debranched starch chains (Am-OSA-St) to control emulsion properties within a pH range suitable for enzymatic catalysis. By adjusting the OSA group density and molecular weight, Am-OSA-St allowed emulsions to transition reversibly between pH 7.3 and 5.5 and enabled self-recycling through supramolecular self-assembly. Employing molecular dynamics simulations and physicochemical characterization, we elucidated the control mechanism of oil-water interfaces via the microstructure transformation of Am-OSA-St. The findings revealed that protonation of carboxylate groups disrupted the charge balance and polarity of starch chains, leading to strong electrostatic and van der Waals interactions that drove self-assembly. This entanglement caused starch chains in the aqueous phase to “drag” those at the oil-water interface, moving them into the aqueous phase and forming micelles. These micelles, with a hydrophobic interior and hydrophilic exterior, prevented re-adsorption. Testing with Candida antarctica Lipase B (CALB) and N-acetylneuraminic lyase showed that the pH-regulated emulsion system maintained excellent efficiency and cycling stability in mild conditions.

Integrated electrochemical and chemical system for ampere-level production of terephthalic acid alternatives and hydrogen

2,5-Furandicarboxylic acid (FDCA), a critical polymer platform molecule that can potentially replace terephthalic acid, coupled hydrogen coproduction holds great prospects via electrolysis. However, the electrosynthesis of FDCA faces challenges in product separation from complex electrolytes and unclear electrochemical and nonelectrochemical reactions during the 5-hydroxymethylfurfural (HMF) oxidation. Herein, an electrochemical/chemical integrated system of alkaline HMF-H2O co-electrolysis is proposed, achieving distillation-free synthesis of high-purity FDCA by acidic separation/purification and hydrogen coproduction. This system achieves ampere-level current densities of 812 and 1290 mA cm−2 at potentials of 1.50 and 1.60 V, with nearly 100% FDCA yield and HMF conversion in only 6 min at 1.50 V. The electrooxidation of HMF involves a coupling of electrochemical and nonelectrochemical reactions, wherein the aldehyde group is dehydrogenated and oxidized, followed by dehydrated and oxidized of the hydroxyl group, ultimately forming FDCA. Concurrently, nonelectrochemical reactions of intermolecular electron transfer occur in HMF and aldehyde group-containing intermediates.

Separation and identification of oligonucleotides impurities and degradation products by reversed phase ultra-high performance liquid chromatography using phenyl-bonded stationary phases without ion pairs - A step towards sustainability

This manuscript discusses the development of a reversed-phase ultra high-performance liquid chromatography (RP UHPLC) method based on phenyl-bonded stationary phases without ion-pairs for the separation and identification of oligonucleotides. The elimination of ion-pair reagents makes the proposed protocol as more compliant to the principles of green chemistry, compared to the traditional ion-pair reversed-phase liquid chromatography methods (IP RP LC). In detail, three phenyl-based stationary phases were tested, namely a C18/AR (a C18 stationary phase with the addition of aromatic groups), a Phenyl-hexyl, and a Diphenyl. Generally, the retention of oligonucleotides increases with the increase of salt concentration and the decrease of the pH, thus confirming the significant impact of van der Waals interactions, salting-out effect, and π-electrons interactions in the retention mechanism. The highest retention and best peak symmetry were observed for the C18/AR stationary phase, while the lowest retention for the Phenyl-hexyl, with retention influenced by the type of salt in the mobile phase. The obtained methods using C18/AR stationary phases allow for the effective separations of positional isomers and for identifying impurities and degradation products using RP UHPLC Q-TOF-MS in a comparatively short time. The application of RP UHPLC Q-TOF-MS provides reasonable selectivity for the resolution of 33 impurities and two degradation products. Both groups of compounds are mainly 3′N and 5′N-shortmers, but in the case of impurities, modifications of cyclic phosphate and phosphate groups were also identified. Nevertheless, Diphenyl and Phenyl-Hexyl may be applied to separate modified oligonucleotides with higher salt concentrations. The proposed separation methods without ion-pair reagents contribute to a more sustainable approach in oligonucleotide analysis.

Design and multi-objective optimization of hybrid process of membrane separation and electrochemical hydrogen pump for hydrogen production from biogas

A new hybrid process for hydrogen (H2) production that including membrane separation, electrochemical hydrogen pump (EHP) and steam methane reforming (SMR) was proposed. Firstly, the combination of two different membranes (PEO-CA) is applied to upgrade the biogas and capture CO2. Secondly, to avoid the toxic effect of CO on the EHP catalyst and, more importantly, to improve the H2 purity, the reforming reaction module is supplemented with water gas shift after the SMR. Finally, EHP is used to achieve high purity hydrogen. Simultaneously, the heat and power integration are considered to improve system efficiency. Sensitivity analysis, maximal information coefficient method and response surface methodology are applied to establish the correlation between objectives and parameters. Then, the second generation multi-objective non-dominated genetic algorithm (NSGA-II) is utilized to achieve minimum levelized cost of hydrogen (LCoH) and carbon emission per unit of hydrogen (ECO2). The optimized LCoH is 2.72 $/kgH2, and the ECO2 is 3.24 kgCO2e. Multi-stage membrane carbon capture process enhances CH4 conversion in SMR. The application of EHP reduces energy consumption and enhances hydrogen yield compared to PSA. The innovative use of membrane is hybridized with EHP to achieve the system intensification. The new hybrid process has a significant advantage in terms of ECO2 (37.45% reduction), although the price is higher compared to conventional biogas-to-hydrogen processes. Thus the new process is a promising low-carbon hydrogen production process from biogas.

The comparative techno-economic and life cycle assessment for multi-product biorefinery based on microwave and conventional hydrothermal biomass pretreatment

Microwave as an efficient and clean energy, is easy integrated with DES pretreatment and biorefinery process to achieve process intensification for cleaner production and sustainable development. However, there are worries about its economic and environmental feasibility for application in biorefinery plant. This work conducted the techno-economic (TEA) and life cycle assessment (LCA) of the entire biorefinery process based on DES pretreatment by microwave heating (MH) for producing glucose, furfural and lignin from lignocellulose, of which the results were compared with conventional heating (CH). For pretreating equivalent biomass, the total yield of products obtained from MH-assisted process was 8.53% higher than that of CH-assisted process due to microwave intensification effect. From the perspective of cradle-to-gate LCA, the MH-assisted process saved energy demand of 5.82%, reducing the environmental impacts global warming (GW) and fossil resource scarcity (FRS) by 4.85% and 5.69%, respectively, relative to CH-assisted process. The main environmental hotspots of both two processes concentrated on the raw material extraction (RME), followed by product separation and solvent recovery (PSSR) stages. Based on economic evaluation, the specific values of TAC regarding one-ton product for MH- and CH-assisted processes were 3194.35 and 3400.37 $/(y⋅t), respectively. Therefore, the MH-assisted pretreatment possessed certain environmental and economic advantages due to product increasement, energy consumption reduction in the DES pretreatment, and burden reduction for subsequent enzyme hydrolysis. Compared to the single-product biorefinery, the multi-product biorefinery strategy was more sustainable and could maximize the advantages of microwave intensification. However, some issues about the design of microwave reactors and temperature monitoring must be considered to pursue scale-up biorefinery plant.

A review on biohydrogen production technology: Production methods, sources, and separation

A review on biohydrogen production technology: Production methods, sources, and separation

Aggregation-induced C–C bond formation on an electrode driven by the surface tension of water

Electrochemical organic synthesis is typically conducted in organic media. The solvent and related supporting electrolytes negatively affect the greenness of electrosynthesis. In this work, with 100% water used as the solvent, we realize aggregation-driven electrochemical radical cross coupling of unsaturated compounds driven by water tension. A key finding is that aggregation of the substrate at the electrode confined the radical intermediate and prevented side reactions, thus providing a way to regulate radical reactions in addition to their native properties. The reaction provides up to 90% yields with almost quantitative chemoselectivity. The pure water system readily yields the products via cold filtration, and the solvent is recycled repeatedly. In particular, the life span of the radical species generated in the reaction increase significantly because of the confined environment in the aggregation state. The greenness of this protocol is further enhanced with readily separation of product from media using cooling and filtration.

Donor-acceptor type of triazine-based conjugated organic polymers with excellent charge separation for efficient photocatalytic production of hydrogen peroxide

Hydrogen peroxide (H2O2) was widely utilized as an environmentally friendly and efficient chemical in various fields. The photocatalytic production of H2O2 using conjugated organic polymers as photocatalysts is promising. However, conjugated organic polymers have limited applications due to the high recombination rate of photogenerated carriers, poor electron mobility rate, and long synthesis time. Herein, we rapidly prepared a novel triazine-based conjugated organic polymer (CTP-TT) for efficient photocatalytic production of H2O2 using a facile sonochemical method. The H2O2 photosynthesis rate of CTP-TT reached 3383 μmol · g−1·h−1 in pure water without the addition of sacrificial agents. The experimental and characterization results confirmed that CTP-TT possessed dual H2O2 production pathways of 2e− oxygen reduction reaction (ORR) and 2e− water oxidation reaction, with 2e− ORR dominating. The theoretical calculations indicated that the excellent charge separation efficiency of CTP-TT was due to its unique donor–acceptor structure. This study provides novel design ideas for improving the photocatalytic performance of conjugated organic polymers, which is expected to promote the development of photocatalytic production of H2O2 applications and the rational design and preparation of organic semiconductor photocatalysts.

A mixed polynuclear clusters-based Y-MOF with an unprecedented (12, 12, 18)-c topology: highly efficient propylene/ethylene separation and iodine adsorption

The design and synthesis of highly stable metal–organic frameworks (MOFs) bearing unpredictable polynuclear clusters and new topologies are important for the development of novel and complicated MOFs. Herein, the polynuclear rare-earth (RE) clusters with more coordination modes and the small V-shaped ligand (2,5-thiophenedicarboxylic acid) were chosen, and subsequently JLU-MOF132 with three different yttrium clusters (two independent Y6 and one Y9 clusters) and a novel (12, 12, 18)-connected topology was successfully synthesized. Notably, JLU-MOF132 exhibits high porosity, excellent thermal, acid-base, and solvent stabilities. JLU-MOF132 shows considerable potential in methanol-to-olefins (MTO) products (C3H6 and C2H4) separation. The high ideal adsorbed solution theory C3H6/C2H4 selectivities (9.2, 10.6, and 15.1) and the breakthrough experiments results, including the high C2H4 purity (>99.9 %) and productivities (26.1, 73.1, and 101.0 L·kg-1), demonstrate its practical purification capability. Semi-empirical tight binding (xTB) quantum chemical calculations explain the mechanisms that differentiate C2H4 and C3H6 adsorption in JLU-MOF132. In addition, JLU-MOF132 also displays outstanding radioactive iodine adsorption performance, with an iodine uptake of 750 mg·g-1 in vapor and 153 mg·g-1 in cyclohexane solutions. Briefly, this work not only demonstrates the viability of employing the V-shaped ligand to increase the structural diversity of highly stable MOFs, but also enhances the application potential of MOFs in the fields of the MTO products separation and radioactive iodine adsorption.

Catalytic hydrogenation of magnesite to methane and magnesium oxide using magnesium carbonate hydroxide as model compound

The hydrogenation of magnesite to CH4 and MgO offers a powerful approach for CO2 direct utilization. To deepen the understanding of the reaction mechanisms, (Mg5(CO3)4(OH)2(H2O)4 was selected as a model compound to gain insights into carbonate hydrogenation. A novel Ni/Fe/ZrO2 catalyst with ferromagnetic properties was employed to facilitate the magnetic separation of the catalyst from the solid products. Thermodynamic simulation and experiments were conducted to address key issues such as gas evolution during catalytic hydrogenation, the effects of catalyst on CH4 selectivity, and the separation of solid products and catalyst. The results indicate that lower temperatures favor CH4 formation, whereas higher temperatures favor CO formation. Increasing Ni loading can enhance the CH4 selectivity. With the presence of 10Ni/Fe/ZrO2 catalyst, 100% CH4 selectivity can be achieved at 300 °C. Moreover, 10Ni/Fe/ZrO2 catalyst exhibits high magnetic responsiveness, facilitating the solid separation and the recycle of the catalyst.

Reaction-controlled Pickering interfacial catalysis: A green route to produce crystalline adipic acid under solvent-free conditions

The pursuit of a greener adipic acid synthesis process, aiming to replace the highly polluting nitric acid oxidation method, has been a longstanding endeavor in both academic and industrial spheres. In this study, we present a reaction-controlled Pickering interfacial catalysis system, enabling the efficient oxidation of cyclohexene to adipic acid using 30 wt% hydrogen peroxide without the involvement of organic solvents. Following the reaction, the system spontaneously undergoes demulsification, facilitating easy recovery of catalyst particles via simple filtration, followed by product separation through cooling-induced crystallization. Employing high speed microscopic imaging for in-situ characterization of interfacial properties, we elucidate the influence of reaction conditions on interfacial properties and catalytic performance. The reaction-controlled Pickering interfacial catalysis system demonstrated herein offers a novel and industrially feasible strategy for developing green adipic acid synthesis route.

تقييم إمكانية االعتماد على نظام السالمة اآللي و صمامات اآلمان لخزانات فصل الزيت الخام في حقل نفط

A crude oil separator is a pressure vessel used to separate oil and gas in an oil well stream. The separators are provided with a Basic Process Control System (BPCS) and a protection system which consists of a Safety Instrumented System (SIS) and a Pressure Relief System (PRS). Failure of the crude oil separator might result in fire, explosion, and toxic dispersions. The world has witnessed several fire and explosion incidents due to the operation of crude oil separators. Reliability of the control and protective systems of crude oil separators is very important to verify their abilities to perform their functions. This technical article presents an overview of the layers of protection of crude oil separator and the reliability of protective systems. The article also presents an evaluation of the reliability of SIS and safety valves of crude oil separators in an oil field. The crude oil separators are arranged in the form of three parallel trains of separators each train divided into three stages. The first stage consists of two separators and each stage of the second and third stages consists of one separator. The reliability of the different configurations of the SIS and safety valves of a train of production separators has been estimated and found to be acceptable.